Cell transformation was examined in C3H 10T1/2 murine fibroblasts and Syrian hamster embryo (SHE) cells.
To determine c-myc, c-fos, ß-actin, glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene expression HL-60 cells were used. Ornithine decarboxylase gene expression was studied in C3H 10T1/2 cells.
1.5 Gy gamma rays radiation was used as a positive transformation response in SHE or C3H 10T1/2 cells.
The positive controls in the gene expression of c-myc and c-fos in HL-60 cells and the gene expression of ornithine decarboxylase in C3H 10T1/2 cells were hyperthermia (45.5°C) and TPA treated cells.
Exposure duration: continuous for 10 , 20 and 40 min
Exposure duration: continuous for 24 h
1.5 Gy of X-ray was used to elicit a positive transformation response in SHE or CH3/10T1/2 cells and as negative control for c-fos expression in HL60 cells. Hyperthermia at 45.5°C for 9 min and TPA at 0.3 µg/ml for 30 min or 50 ng/ml for 3 h were used as treatments modifying the expression of c-myc, c-fos and ODC.
|Exposure duration||continuous for 10 , 20 and 40 min|
|Additional info||HL60 cells were exposed. Reference Article: Little JB, Nagasawa H, Kennedy AR. DNA repair and malignant transformation : effect of X radiation , 12-O-tetradecanoyl-phorbol-13-acetate, and protease inhibitors on transformation and sister-chromatid exchanges in mause 10 T1/2 cells.|
|Exposure room||water bath insulated with styrofoam ( 1.2 m long, 0.7 m wide, 11 cm deep) maintained at 37°C.|
|Setup||solenoids, 38.7 cm long, 12 cm in diameter, 199 turns; tissue culture flasks were placed horizontally in the central planes of long solenoids wound on thin-walled plexiglas cylinders enclosed in magnetic shield cylinders (22.9 cm in diameter), all of them were placed parallel to each other in water bath; cells were parallel to the field lines which was uniform along the 18 cm long central plane.|
|Sham exposure||A sham exposure was conducted.|
|Additional info||Control cells experienced zero magnetic field but were subjected to the same level of disturbance such as local acoustic noise and convective heating.|
|magnetic flux density||200 µT||unspecified||measured||unspecified||-|
No transformed colonies were found in SHE cells exposed to 60 Hz magnetic fields.
There were no significant differences in plating efficiency among exposed and sham exposed C3H 10T1/2 cells. Incubation in TPA enhanced the transformation induced by 1.5 Gy gamma rays radiation. TPA incubation in exposed and sham exposed cells alone had no effect.
Exposure to 60 Hz magnetic fields had no effect on ornithine decarboxylase gene expression whereas treatment with TPA increased ornithine decarboxylase transcription level in exposed and sham exposed SHE cells.
No statistically significant effects were observed in gene expression in HL-60 cells exposed to 60 Hz magnetic fields.